Dopamine enhances multisensory responses in the dorsomedial striatum

The brain operates with simultaneous different sensory modalities in order to engage adaptive responses. However, the question of how (and where) multisensory information is integrated remains unanswered. In the dorsomedial striatum, single medium spiny neurons (MSNs) are excited by tactile and visual inputs; however, the mechanism which allows the integration of these responses and how they are shaped by dopamine is unknown. Using in vivo optopatch-clamp recordings, we study how dopamine modulates tactile, visual and simultaneous bimodal responses in identified MSNs and their spontaneous activity. Results show that dopamine enhances bimodal responses, specifically in direct pathway MSNs, through the acceleration of the visual responses. We provide anatomical and computational evidence suggesting that this relies on the disinhibition of direct MSNs by a cell-type-specific corticostriatal pathway. Altogether, our in vivo, in silico and tracing results propose a new mechanism underlying the synchronization of multimodal information mediated by dopamine.